JPS60110834A - Titanium alloy and treatment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

The present invention utilizes a horn alpha beta titanium alloy, particularly a temporary suspension beta stabilizer and a titanium alloy containing at least 63% 1
- Concerning the treatment of Libdene and existing alpha-beta alloys. High strength titanium alloys are widely used for aircraft applications. An example of its application is disks in gas turbine engines. The disk of the gas turbine engine is placed around the /c compressor blades and restrains them at 1000rpm.
It is rotated with a haste of the order of n+. During operation, substantial stresses are generated and these saws are usually partially repetitive. It is known that such fluctuating stress causes fatigue failure. In normal fatigue failure situations, cracks usually initiate at surface or near-surface cracks or flaws.
The crack then grows or propagates as a result of the varying stresses. C0 crack growth reduces the area of metal available to resist stress, thereby increasing the effect of the J stress and causing a more rapid crack growth rate. It is clearly desirable that no fatigue failure occurs. However, this is usually not possible. It is impossible to rely on the absence of fatigue failure in applications where fatigue failure poses a danger. Therefore, it is desirable for fatigue cracks to grow as slowly as possible after their initiation. Slow crack growth rates allow detection of such cracks during periodic inspection before failure occurs. Improves various mechanical properties of titanium alloys.

[] Hiss exists. Most of these processes have focused on the static properties of titanium, such as yield and tensile strength and creep properties. The present invention is based on a widely used titanium alloy, Ti6-2.
-'l-6, with particular focus on the issue of crack growth rates within
ing. No. 2 U.S. patent in the field of Bhutan alloy,
', '368, No. 586 and No. 2,974,076
'/] describes tJ, Norfno v-beta titanium alloys and their various heat treatment processes. Rice 1j, I Q! +','16ft2.97/1.0
No. 76 includes heat treatment 1! which includes quenching from a temperature above the beta transus temperature! I! is Beta 1~Hunzas (tra
++sus) Warm! It is stated below that C is undesirable because it reduces the tensile strength and ductility of C alloys compared to Karano quenching (Column 3 of the last full paragraph).
). Claims 8 and 9 of U.S. Pat. Heat treatments are described that include equilibration and rapid quenching at temperatures near but below the beta transus temperature. Deformation above the beta transus temperature is not described. U.S. Patent No. 2,968.5
In June 1986, quenching of C was described as a method to produce the WidmanstatLc++ structure, and the temperature ranged from about 1.7 to 16.6 °C per minute (from about 3 below per minute to about 30 below per minute). ) is disclosed, the cooling rate of (
Column 39 rows 23-25. U.S. Patent Nos. 3,901.7/13 and 4.053.
No. 330 describes the treatment of titanium alloys. U.S. Pat. No. 3,901.743F>t, especially Ti-6-2-
4-6 Explaining the materials: 3 CJs, and 3 forged materials
Starting at 1, solution heat treatment at a temperature slightly below Beta [-Ranzas (946 ° C < 17
35'F) and the suggested heat treatment is 871-9
27°C (1600-1700'F)), quenching to room temperature and 760-871°C (1470'F).
(lower) followed by reheating to 510-593°C (95
0-1100'F). Therefore, there is nothing in this document that predicts the present invention described later. U.S. Patent No. 11,053.330
The process described in that issue includes forging at temperatures above the beta transus temperature, rapid quenching to produce multi-bijoite molding, and tempering at intermediate temperatures. Quenching is performed at 50℃ for 1 minute (10℃ for 1 minute).
The quenching rate of A-Goo (00 pieces) is disclosed as being carried out using a ligneously produced liquid medium. US special 1. T No. 4.309.226 is a mechanical heat treatment for the treatment of near-alpha-butan alloys and especially as I would like to explain some known alloys. Although this 1-res is similar to the /1 alloy of the present invention in many cases, it is an alloy that is substantially different from the alloy to which the present invention is directed. The target is a certain near-alf alloy.Therefore, the result obtained by -tere is LJ,
This differs from the results obtained by applying this norocess to alloys of the type described in this invention. In particular, low M
Due to the O-containing M, there is no formation of MO-rich boundary layer observed in the aqueduct N1 treated according to the present invention. According to the invention, 'li-6AI-2811-47
A titanium alloy in the form of 1"-6M0 is heat treated to produce increased resistance to crack growth. Forged in the material TiL Beta "Lanzas"-
11~b 1n) through beta transus? ll' cold N1, heat treated near but below beta transus, and aged. The resulting tubed structure consists of alpha ν platelets within the beta matrix.
) is ffi/υ, and the platelet is surrounded by an MO-rich zone, and does not contain grain boundary alpha up to 414 at -. This structure has a resistance to fatigue crack propagation of 4jJ. Other features and advantages are indicated in the claims and will become more apparent from the following description of an embodiment with the aid of the drawings.
Ro-),. The present invention is a mechanical heat treatment process for imparting improved mechanical properties to certain titanium alloys. Wood 1] Hiss is 6%△1.2%Sn, 4%Zr,
6%Mo, 15% J-SiTTi (Ti-6-
The I4q component of 2-4-6) was discovered and optimized with respect to the alloy, and will be explained with respect to this alloy. The range of element contents in this commercially available alloy is all ±0.5% from the ajf content with the exception of 10.25% C for S11. It is believed that several other alloys are suitable for the 6-piece process. The principal other commercially available alloy believed to be suitable for the present invention is Q gold, designated 1-i-17, which has a standard composition of 5% Δ1. 2%3n
,, 2% Zr, 4% Mo, /1%01゛, the remainder is mainly -'i. The range of element milling is ±0 for 3n and 7r
．． 0.5%, with the exception of 25%. These two alloys are alpha-beta alloys with high beta stabilizer contents such that the beta phase is relatively stable. These alloys are alloys with high hardenability, and their hardened parts are completely hardened by quenching from a beta solvus temperature or higher. State (2:・3
%) is also of right significance. The first step in the process is a forging step carried out at a temperature above the beta transus temperature, preferably from about 1/1 degree Celsius above the beta [run I7'' temperature to 36 degrees Celsius (approximately 25 to 65 degrees below). Temperature forging was carried out using a heated die, but reasonable forging temperature variations, particularly within the range of 14" to 36 °C (25 to 65 below), are not suitable for the present invention. Within range. The magnitude and rate of deformation are selected to be sufficient to recrystallize the material and create coarse/C grain boundaries. An equivalent reduction, such as an area reduction of typically at least 10%, more preferably at least 25%, is sufficient. Following the isothermal deformation process, the material is heated at a controlled rate to an isothermal forging temperature (preferably below about 1000°C).
cooled from The speed is approximately 11°C (20'F) per minute.
) to about 50°C (100°C). This controlled cold cooling process is critical to achieving the desired micro-pore formation as described below. If the speed is too high, the desired I-shaped structure will not be formed.Then the r 44 stone will be about 0. 5 to 5 hours at a temperature close to but below the libeta transus temperature,
, L beta tran) As selection degree J, rim approximately 28℃ (50
below) to about 83℃ (150 below), i(
'Heat treated. The material is cooled from the above heat treatment temperature at a rate equal to or faster than that produced by air cooling R1 (to about 260° C. or below 500° C.). ?J] is carried out. The final process of
It is a 1-sink process that takes place at temperatures from 900 °C to approximately 849 °C (below 1200 °C). The alpha-phase platelet length-to-thickness ratio is controlled by the initial isothermal forging temperature and the cold fJI rate, and ranges from about 4 to about 20%. However, if the speed is too expensive, the plate left will be too thin (1/d is too expensive) and will not produce the desired properties. Resistance′
It leads to a rough structure without C. The structure in Figure 1 is observed after crack formation, which is observed along the interface between the needle and the beta matrix layer (as shown in Figure 1).For this reason, It is desirable that the plate leg 1- is not too sharp, and that the plate t-leg 1- is in the right shape so that it is not pulled. If the length of the play 1-let is relatively short, then the platelets [- are irregularly oriented toward each other in the direction ≧ t.
), the crack propagation path will be twisted and the crack propagation will be slowed down. Treatment IU according to the present invention! One observed feature of the developed material is the presence of a thin layer of U-diffused composition at the interface between the alphanuclear platelets and the betatontrix. This interface composition is 20 to 2 in terms of vehicle suspension ratio.
It has a high molybdenum content of 5% A-da. This material is tough, ductile and resistant to crack growth, and the present invention provides substantial benefits as a result of this interphase. Believe it 1, this high molywood / Den 911 and ¥81 a month is a heat treatment room J ■
! It is believed that the number of particles generated during the process is 1:3. , n (J, 10'mm (1000△) A-da. Its high molybdenum content f1 is 1.: 3%) [libdenum 1, novel fJ-free alloys are treated according to the invention with 8t1.1. : 01 ni'
It is expected that the l' i -〇-2-/I-6 material will not produce the desired r[1-crack growth behavior. Some of the benefits of the invention are illustrated in the following examples. Ti -6-2-4~C5'ell ill (approximately 94
6℃ (below 5735) Approximately 66% of those with Beta F-Ranzas (1) u'ii fPim Small Mat
'982℃ (1800'F) 1-OOoF)
(7) Temperature approximately 22℃ for 11 minutes (/IO'F>'7)
cooled at speed (and then air cooled to room temperature)
. Samples of this material were 866℃ (1590 pieces) and 916℃
(1680'F) (7) IH16') Various (7) temperatures tfr, i.e. from about 80.5°C (145°F) to about 30°C.
It was heat treated at lower temperatures than Beta 1 Heranzas up to 5°C (below 55°C). Most of the sample was then removed for 8 hours.
93℃(1100,”F) te, 'll-shin'jcl
t, was also tested to obtain a relative indication of the crack growth rate (IC), the results of which are shown in Figure 2. It has been found that temperatures as low as 61°C (110'F) produce optimal crack growth rates.
593℃ (1100'F) cx-sink a/j
It is observed that Sample Also in the curve are standard conventional treatments including oil cooling from 982°C (1800'F) followed by heat treatment at <830'C (below 1525°C). . Reveal the wood. It is clear that the +/J ¥31 of the present invention is substantially lower than the known 4A1. (Liebsolvus solution treatment, rapid 10J 1.093℃ (5100 below)
J-zinc) to J, treated tanned material 11.
time vs. 1% Creel Larson-Mil
ler block 1- is shown.For similar temperature and stress profiles 1'1, the advantage of the present invention is that the creep rate is about twice as high as that of known materials. In another test C, the crack growth rate was evaluated as a function of 'C' i? Again, the material of the present invention can be used in a well-known shrine (the same known material as the material in Figure 3). It is observed that the number of cases decreases with the increase of wetlands.Since the present invention has been described above and is not limited to specific embodiments, the variations of the gods are within the scope of the present invention. It will be understood that 0 out of 1 is done and 1! is done.

[Brief explanation of the drawing]

FIG. 1 is a photomicrograph of a specimen treated with J2 according to the present invention. Fig. 2 shows the processed king i-6-4-2- under various conditions.
FIG. 6 is a diagram showing the crack growth life for six materials. FIG. 3 is a diagram comparing the cracking rate for the known process and the cracking rate for the material of the present invention. FIG. 4 is a comparison of crack growth rate as a function of temperature for a material treated in accordance with the present invention and a conventionally treated material. Patent Applicant United Knowledge Cohoraison Agent Patent Attorney Masaaki Akashi FIG, 100X C;

Claims (3)

[Claims] (1) Beta stabilizer of substantial m and at least 3
In a method for improving the crack growth behavior of alpha-j-beta titanium materials containing % MO and controlling the beta transition temperature. a, the process of creating a material with Beta[-Ranzas or higher in sufficient quantities to produce rrJ crystallization,
The process of cooling U, 11 through Beta Transus at a rate of about 11°C (20° C.) to about 55° C. (100° C.) per minute; The process of heat treating the material at temperatures as low as 28°C (50°C) to about 83'C (150°C) and cooling the alloy at a rate equal to or greater than that produced by air-cooled IJI. and e, a step of aging the monthly interest. (2) Titanium alloy article (standard composition 6%△1.2%S11
．． 71% 7r, 6% MO1 residual main and TTt), in a method for processing and heat treating a, gamma prime solvus or higher, about 14'C
The process of forging the monthly rate at fdIi ■ with an area reduction of at least 10% at a temperature between 5°C and about 36°C (65°C), and b. about 11°C (20°C) per minute. Approximately 55°C (100
'F) and cooling the material to below about 538 °C (1000 °C) at a rate between C0 below gamma prime solvus at approximately 28°C (50'F) and 83°C (below 150'C) for approximately 0.5 to 5 hours.
The process of heat treating the material at temperatures between d and air cooling f
Cool the material to below about 260°C (500°C) at a speed equal to or exceeding that produced by Jj.
C8 about 482°C (900°[) and about 649°C (1200°
A patent characterized in that it comprises a process of kneading and refrigeration of the material for about 2 to 10 hours at a temperature between (3) The titanium alloy article that provides resistance to crack growth contains a C1a beta matrix, which has an average content of 1/(1) between about 4 and about 20. having about 2
0 to about 90 volume percentages of alpha platelets, C9 said needle is surrounded by a thin layer having a high MO content, and d said monthly rate is a continuous grain. Contains substantially the alpha phase of the field/υ
Not there. It is characterized by titanium alloy articles.